Fan Impeller and Fan Using Fan Impeller

ABSTRACT

The present invention discloses an impeller for a fan, which comprises a plurality of blades (2) and a rear wheel disc (1); the plurality of blades (2) are arranged one by one successively along a circumferential direction of the rear wheel disc (1); an angle α is defined between the first projection line (21a) of each outer edge (21) and a radial line of the rear wheel disc (1) and satisfies the following condition: −60°≤α≤60°; an angle β is defined between the second projection line (22a) of each inner edge (22) and the radial line of the rear wheel disc (1) and satisfies the following condition: 20°≤β≤70°; an angle θ is defined between a first connecting line (L1) and a second connecting line (L2) and satisfies the following condition: 10°≤Θ≤65°. The impeller for a fan is good in aerodynamic performance, high in both fan efficiency and air pressure, and large in gradient of the generated negative pressure.

RELATE APPLICATIONS

This application is a national phase entrance of and claims benefit toPCT Application for an impeller for a fan and a fan using the same,PCT/CN2017/000133, filed on Jan. 24, 2017, which claims benefit toChinese Patent Applications 201610072261.3, filed on Feb. 1, 2016. Thespecifications of both applications are incorporated here by thisreference.

FIELD OF THE INVENTION

The present invention relates to a fan, and in particular to an impellerfor a fan and a fan using the same.

DESCRIPTION OF THE PRIOR ART

A fan is an important part of a range hood. An impeller for the fanrealizes energy conversion, and the performance of the impeller directlyinfluences the performance of the range hood. At present, conventionalimpellers for range hoods are usually formed by stamping flat plateswhich are then connected by buckling their two ends, and blades aregenerally machined into a circular arc in a uniform thickness. Since therotation speed of the impeller generally exceeds 800 RPM, the actualfluid separation and reflux between blades is obvious. Moreover, sincethe impeller functions to pre-whirl gas and the gas will graduallychange its direction in the process of flowing into the impeller tochange its direction by 90°, the simple consistence in angle of an inletand an outlet is disadvantageous for the actual performance of theimpeller. In order to improve the fan efficiency, many improvements havebeen made to the structure of the impeller. However, these improvementsare still limited to the binary flow technology, so that the efficiencyimprovement of the fan is limited, and the technical level of ordinarybinary impellers will significantly influence the performance of thefan. Therefore, the defects of the binary impellers cannot befundamentally overcome at present. In addition, if the structure of theimpeller is not changed fundamentally, at the same air pressure, theoverall structure of the fan is not compact enough and is relativelylarge in size. Accordingly, it is necessary to further improve thestructure of the existing impellers and fans.

SUMMARY OF THE INVENTION

A first technical problem to be solved by the present invention is, inview of the prior art, to provide an impeller for a fan, which is novelin structure and good in aerodynamic performance.

A second technical problem to be solved by the present invention is, inview of the prior art, to provide a fan which is compact in structureand high in both fan efficiency and air pressure.

To solve the first technical problem, the impeller for a fan comprises:a plurality of blades, each blade has a top, a bottom, an outer edge,and an inner edge; and a rear wheel disc with a surface, a periphery,and a center, the plurality of blades mounted on the rear wheel disc, afirst projection line being defined on the rear wheel disc and by theouter edge of each blade, a second projection line being defined on therear wheel disc and by the inner edge of each blade; wherein the outeredge of each blade is placed adjacent to the periphery of the rear wheeldisc and the inner edge of each blade is adjacent to a center of therear wheel disc, the bottom of each blade stands on the surface of therear wheel disc, and is the plurality of blades are arranged one by onesuccessively along a circumferential direction of the rear wheel disc;the outer edge of each blade is an air exit, and an angle α is definedbetween the first projection line of each outer edge and a radial lineof the rear wheel disc and satisfies the following condition:−60°≤α≤60°; the inner edge of each blade is s an air intake, and anangle β is defined between the second projection line of each inner edgeand the radial line of the rear wheel disc and satisfies the followingcondition: 20°≤β≤70°; an angle θ is defined between a first connectingline connecting the outer edge of a blade and the center of the rearwheel disc and a second connecting line connecting the inner edge of ablade and the center of the rear wheel disc and satisfies the followingcondition: 10°≤θ≤65°; and, a first vertical height h1 of the top of eachouter edge is less than a second vertical height h2 of the top of eachinner edge.

Preferably, the outer edge of each blade is disposed adjacent to theperiphery of the rear wheel disc; the inner edge of each blade isslanted downwardly toward the center of the rear wheel disc; each bladehas a bottom surface all of which are located in a same plane; and, eachblade has a smooth top surface.

Preferably, a ratio of the first vertical height h1 to the secondvertical height h2 satisfies the following condition: 0.2≤h1/h2≤0.8.

In order to further improve the aerodynamic performance of the impeller,the angle α satisfies the following condition: −30°≤α≤30°; the angle βsatisfies the following condition: 30°≤β≤60°; the angle θ satisfies thefollowing condition: 20°≤β≤70°; and, the ratio of the first verticalheight h1 to the second vertical height h2 satisfies the followingcondition: 0.4≤h1/h2≤0.6.

According to the size of the impeller and different parameter ranges,the number of blades may be different. Preferably, the plurality ofblades comprises 10 to 50 blades.

As a preferred solution of any one of the above solutions, the impellerfor the fan further comprises a front cover covering the plurality ofblades; a first arc segment and a second arc segment that are jointedwith each other from inside to outside are formed at an intersection ofthe front cover with a meridian plane of a rotating shaft of theimpeller; and, a ratio of the radius R1 of the first arc segment to theradius R2 of the second arc segment satisfies the following condition:0.1≤R1/R2≤0.6.

Further preferably, a linear segment, which is disposed on an outer sideof the second arc segment and smoothly jointed with the second arcsegment, is further formed at the intersection of the front cover withthe meridian plane of the rotating shaft of the impeller; and, a ratioof the length L of the linear segment to the radius R2 of the second arcsegment satisfies the following condition: 0.1≤L/R2≤0.4. By providingthe linear segment, it is convenient for machining the front cover, andthe formation of a boundary layer at an end wall of the front cover canalso be controlled.

To solve the second technical problem, the A fan using the impeller fora fan, comprises a volute, a motor and a wind inlet ring; wherein theimpeller for the fan is disposed inside the volute; the rear wheel discof the impeller for the fan is disposed on an output shaft of the motor,and the wind inlet ring is disposed at a wind inlet of the fan andfitted with a front cover of the impeller for the fan.

In order to improve the fan efficiency, a distance δ between the rearwheel disc and the volute close to the rear wheel disc satisfies thefollowing condition: 1 mm≤δ≤10 mm.

In order to further improve the fan efficiency, the front cover iscovered outside the wind inlet ring, and a vertical distance Δ between afront edge of the front cover and an outside wall of the wind inlet ringsatisfies the following condition: 0.5 mm≤Δ≤5 mm.

Compared with the prior art, the present invention has the followingadvantages: in the impeller for a fan, a plurality of blades arearranged one by one successively along a circumferential direction of arear wheel disc; an angle defined between a projection line of the outeredge and the inner edge of a blade and the center of the rear wheel discsatisfies a certain parameter range; an angle defined between a firstconnecting line connecting the outer edge of a blade and the center ofthe rear wheel disc and a second connecting line connecting the inneredge of a blade and the center of the rear wheel disc and satisfies acertain parameter range; and, the inner edge of a blade is higher thanthe outer edge. The impeller for a fan is novel in structure and good inaerodynamic performance. The fan using this impeller is compact instructure, small in size, high in both fan efficiency and air pressure,and large in gradient of the generated negative pressure. When the fanis applied to a range hood, the escape of oil smoke can be preventedeffectively, and the oil smoke extraction rate of the range hood can beimproved greatly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an impeller for a fan according toEmbodiment 1 of the present invention;

FIG. 2 is a top view of the impeller for a fan shown in FIG. 1;

FIG. 3 is a side view of the impeller for a fan shown in FIG. 1;

FIG. 4 is a schematic structure view of backward inclination of an airexit of each blade according to Embodiment 1 of the present invention;

FIG. 5 is a schematic structure view of forward inclination of the airexit of the each blade according to Embodiment 1 of the presentinvention;

FIG. 6 is a schematic view of the projection of an air intake of eachblade on a meridian plane of the impeller according to Embodiment 1 ofthe present invention;

FIG. 7 is a sectional view of the impeller for a fan shown in FIG. 1;

FIG. 8 is another sectional view of the impeller for a fan shown in FIG.1;

FIG. 9 is a schematic view of the projection of each blade on themeridian plane of the impeller according to Embodiment 1 of the presentinvention;

FIG. 10 is a perspective view of a fan using the impeller according toEmbodiment 1 of the present invention;

FIG. 11 is an exploded view of the fan shown in FIG. 10;

FIG. 12 is a sectional view of the fan shown in FIG. 10; and

FIG. 13 is a s perspective view of an impeller for a fan according toEmbodiment 2 of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

To enable a further understanding of the present invention content ofthe invention herein, refer to the detailed description of the inventionand the accompanying drawings below:

FIG. 1-FIG. 3 show a preferred Embodiment 1 of an impeller for a fanaccording to the present invention. In this embodiment, the impeller fora fan is a closed impeller. The impeller comprises a plurality of blades2, each blade 2 has a top, a bottom, an outer edge 21, and an inner edge22; a rear wheel disc 1 with a surface, a periphery, and a center, theplurality of blades mounted on the rear wheel disc 1, a first projectionline being defined on the rear wheel disc 1 and by the outer edge 21 ofeach blade 2, a second projection line being defined on the rear wheeldisc 1 and by the inner edge 22 of each blade 2; and a front cover 3covering the plurality of blades 2. The plurality of blades 2 aredisposed between the rear wheel disc 1 and the front cover 3. The bottomof each blade 2 stands on the surface of the rear wheel disc 1.

In this embodiment, the plurality of blades 2 comprises 10 to 50 blades.The bottom of each blade 2 stands on the surface of the rear wheel disc1 and the plurality of blades 2 are arranged one by one successivelyalong a circumferential direction of the rear wheel disc 1. The surfaceof the rear wheel disc 1 is of a planar structure, and each blade 2 hasa bottom surface 23 all of which are located in a same plane. The outeredges 21 of each blade 2 disposed adjacent to the periphery of the rearwheel disc 1, that is, the outer edge 21 of each blade is not slantedinward or outward relative to the rear wheel disc 1, and the inner edge22 of each blade 2 is slanted downwardly toward the center of the rearwheel disc 1.

The outer edge 21 of each blade 2 is an air exit, and an angle α isdefined between the first projection line 21 a of each outer edge 21 anda radial line of the rear wheel disc 1 and satisfies the followingcondition: −60°≤α≤60°, preferably −30°≤α≤30°. The direction shown by thearrows in FIGS. 4 and 5 is a direction of rotation of the impeller. Asshown in FIG. 4, the angle α of the outer edge 21 is positive; and, asshown in FIG. 5, the angle α of the outer edge 21 is negative. In thisembodiment, α=0°, that is, the angle of the air exit of each blade is0°. As shown in FIG. 6, the inner edge 22 of each blade 2 is s an airintake, and an angle β is defined between the second projection line 22a of each inner edge 22 and the radial line of the rear wheel disc 1 andsatisfies the following condition: 20°≤β≤70°. In order to furtherimprove the aerodynamic performance, the included angle β satisfies thefollowing condition: 30°≤β≤6°. In addition, as shown in FIG. 7, an angleθ is defined between a first connecting line L1 connecting the outeredge of a blade and the center of the rear wheel disc 1 and a secondconnecting line L2 connecting the inner edge of a blade and the centerof the rear wheel disc 1 and satisfies the following condition:10°≤θ≤65°, preferably 20°≤θ≤45°.

As shown in FIG. 8, the front cover 3 is of a trumpet mouth structurewhich expands outward from the middle. Specifically, a first arc segment31, a second arc segment 32 and a linear segment 33 that are smoothlyjointed with each other from inside to outside are formed at anintersection of the front cover 3 with a meridian plane of a rotatingshaft of the impeller. A ratio of the radius R1 of the first arc segment31 to the radius R2 of the second arc segment 32 satisfies the followingcondition: 0.1≤R1/R2≤0.6; and a ratio of the length L of the linearsegment 33 to the radius R2 of the second arc segment 32 satisfies thefollowing condition: 0.1≤L/R2≤0.4. After the above structural parametersare used in the front cover 3, the aerodynamic performance of theimpeller may be better. In addition, by the linear segment 33, it isconvenient for machining the front cover, and the formation of aboundary layer at an end wall of the front cover can also be controlled.

As shown in FIG. 8 and FIG. 9, a first vertical height h1 of the top P1of each outer edge 21 is less than a second vertical height h2 of thetop P2 of each inner edge 22, and a ratio of the first vertical heighth1 to the second vertical height h2 satisfies the following condition:0.2≤h1/h2≤0.8, preferably 0.4≤h1/h2≤0.6. Furthermore, each blade 2 has asmooth top surface 24 which is sunken inward in its center, and the topsurface 24 is between the top of the inner edges 22 and the top of theouter edges 21.

FIG. 10-FIG. 12 show a preferred embodiment of a fan using the impellerfor a fan according to Embodiment 1 of the present invention. In thisembodiment, the fan comprises a volute 4, a motor 5 and a wind inletring 6. The impeller for the fan is disposed inside the volute 4. Therear wheel disc 1 of the impeller for the fan is disposed on an outputshaft of the motor 5 and locked by a nut 7. The wind inlet ring 6 isdisposed at a wind inlet of the fan. The front cover 3 is coveredoutside the wind inlet ring 6, and a wind outlet hood 8 is disposed atthe wind outlet of the fan.

In order to improve the fan efficiency, in this embodiment, a distance δbetween the rear wheel disc 1 and a wall 41 close to the rear wheel disc1 satisfies the following condition: 1 mm≤δ≤10 mm; and, a verticaldistance Δ between a front edge of the front cover 3 and an outside wallof the wind inlet ring 6 satisfies the following condition: 0.5 mm≤Δ≤5mm. The tests show that the fan efficiency is maximized after thestructural parameters of the fan are within the above numerical ranges.

Embodiment 2

FIG. 13 shows Embodiment 2 of the impeller for a fan according to thepresent invention. In this embodiment, the impeller for a fan is an openimpeller. The impeller comprises a rear wheel disc 1 and a plurality ofblades 2. Compared with the impeller for a fan in Embodiment 1, in thisimpeller, the front cover is omitted. The remaining structure is thesame as the structure in Embodiment 1 and will not be repeated here.

The foregoing description merely shows preferred embodiments of thepresent invention. It should be noted that various modifications orimprovements may be made to the present invention by a person ofordinary skill in the art without departing from the principle of thepresent invention, for example, the blades of the impeller may be of aplanar structure, and these modifications or improvements shall fallinto the protection scope of the present invention.

1. An impeller for a fan, comprising: a plurality of blades, each bladehas a top, a bottom, an outer edge, and an inner edge; and a rear wheeldisc with a surface, a periphery, and a center, the plurality of bladesmounted on the rear wheel disc, a first projection line being defined onthe rear wheel disc and by the outer edge of each blade, a secondprojection line being defined on the rear wheel disc and by the inneredge of each blade; wherein the outer edge of each blade is placedadjacent to the periphery of the rear wheel disc and the inner edge ofeach blade is adjacent to a center of the rear wheel disc, the bottom ofeach blade stands on the surface of the rear wheel disc, and theplurality of blades are arranged one by one successively along acircumferential direction of the rear wheel disc; the outer edge of eachblade is an air exit, and an angle α is defined between the firstprojection line of each outer edge and a radial line of the rear wheeldisc and satisfies the following condition: −60°≤α≤60°; the inner edgeof each blade is s an air intake, and an angle β is defined between thesecond projection line of each inner edge and the radial line of therear wheel disc and satisfies the following condition: 20°≤β≤70°; anangle θ is defined between a first connecting line connecting the outeredge of a blade and the center of the rear wheel disc and a secondconnecting line connecting the inner edge of a blade and the center ofthe rear wheel disc and satisfies the following condition: 10°≤θ≤65°;and, a first vertical height h1 of the top of each outer edge is lessthan a second vertical height h2 of the top of each inner edge.
 2. Theimpeller of claim 1, wherein the outer edge of each blade is disposedadjacent to the periphery of the rear wheel disc; the inner edge of eachblade is slanted downwardly toward the center of the rear wheel disc;each blade has a bottom surface all of which are located in a sameplane; and, each blade has a smooth top surface.
 3. The impeller ofclaim 1, wherein a ratio of the first vertical height h1 to the secondvertical height h2 satisfies the following condition: 0.2≤h1/h2≤0.8. 4.The impeller of claim 3, wherein the angle α satisfies the followingcondition: −30°≤α≤30°; the angle β satisfies the following condition:30°≤β≤60°; the angle θ satisfies the following condition: 20°≤θ≤45°;and, the ratio of the first vertical height h1 to the second verticalheight h2 satisfies the following condition: 0.4≤h1/h2≤0.6.
 5. Theimpeller of claim 1, wherein the plurality of blades comprises 10 to 50blades.
 6. The impeller of claim 1, further comprising: a front covercovering the plurality of blades; a first arc segment and a second arcsegment that are jointed with each other from inside to outside areformed at an intersection of the front cover with a meridian plane of arotating shaft of the impeller; and, a ratio of the radius R1 of thefirst arc segment to the radius R2 of the second arc segment satisfiesthe following condition: 0.1≤R1/R2≤0.6.
 7. The impeller of claim 6,wherein a linear segment, which is disposed on an outer side of thesecond arc segment and smoothly jointed with the second arc segment, isformed at the intersection of the front cover with the meridian plane ofthe rotating shaft of the impeller; and, a ratio of the length L of thelinear segment to the radius R2 of the second arc segment satisfies thefollowing condition: 0.1≤L/R2≤0.4.
 8. A fan using the impeller of claim6, comprising a volute, a motor and a wind inlet ring; wherein theimpeller for the fan is disposed inside the volute; the rear wheel discof the impeller for the fan is disposed on an output shaft of the motor;and, the wind inlet ring is disposed at a wind inlet of the fan andfitted with a front cover of the impeller for the fan.
 9. The fan ofclaim 8, wherein a distance δ between the rear wheel disc and a wall ofthe volute close to the rear wheel disc satisfies the followingcondition: 1 mm≤δ≤10 mm.
 10. The fan of claim 8, wherein the front coveris covered outside the wind inlet ring, and a vertical distance Δbetween a front edge of the front cover and an outside wall of the windinlet ring satisfies the following condition: 0.5 mm≤Δ≤5 mm.